538 MM. Pelouze and Maurey on the New Methods 



The cotton is transferred from the strainer to the third com- 

 partment ; then, when it is in sufficient quantity to fill this 

 almost entirely, it is withdrawn and placed in vessels, where it 

 remains forty-eight hours. These vessels are surrounded by 

 water, so that the temperature never experiences such an eleva- 

 tion as to produce decomposition. 



The contents of these vessels are placed in a machine, the 

 rotation of which expels in a few minutes three-fourths of the 

 non-combined acid. These weakened acids are not further 

 used in the manufactory ; they are supplied to a contractor, who 

 gives in return concentrated sulphuric acid. 



To remove the remainder of the acids, the cotton is washed by 

 agitating it in a current of water, and leaving it immersed for 

 six weeks. At the expiration of this time the cotton is again 

 dried by rotation, then soaked in a boiling solution of carbonate 

 of potass of 2° Baume, and treated with pure water until there 

 is no alkaline reaction. 



Finally, after a third and last drying by rotation, the cotton 

 is dried in the air when the weather is suitable, otherwise in an 

 oven whose temperature does not exceed 20°. 



This is General von Lenk's method. 



At Bouchet the same operations were effected in the same 

 order, but with the following differences : — (1) in the proportion 

 of the cotton to the acids, as explained above ; (2) in the duration 

 of the impregnation, which was one hour instead of forty-eight ; 

 (3) in that of the washing in the current of water (an hour or 

 an hour and a half instead of six weeks) ; (4) in the machine for 

 removing the acids and the water, which were presses instead of 

 rotating machines ; (5) in the mode of neutralizing the last traces 

 of acids ; with this view a cold ley of ashes was used, in which 

 the cotton was immersed for twenty-four hours, while General 

 von Lenk boils it for a few minutes in a solution of carbonate of 

 potass. 



We may here reply to an assertion in a German Report, with 

 an English translation of which General Lenk has furnished us. 

 It is there pretended that the French cotton retained, after wash- 

 ing, so much free acid, that a layer of wood ashes was neutralized 

 by contact with it, and became acid after long usage. A cotton 

 which, like that manufactured at Bouchet, had remained for 

 twenty-hours in an alkaline ley could not produce such a result. 



The use of rotators has the advantage over presses of not 

 spoiling the fibres of cotton. A better-looking preparation may 

 thus be obtained, but this modification has no influence on the 

 chemical composition. 



We shall not discuss the other differences between the me- 

 thod of Bouchet and that of Hirtenberg. The most certain 



